Field
Embodiments of the present disclosure generally relate to a permanent magnetic mask chuck, and more particularly, a permanent magnetic mask chuck suitable for use in a vertical and other processing systems.
Description of the Related Art
Opto-electronic devices that make use of organic materials are becoming increasingly desirable for a number of reasons. Many of the materials used to make such devices are relatively inexpensive, so organic opto-electronic devices have the potential for cost advantages over inorganic devices. As well, the inherent properties of organic materials, such as their flexibility, may be advantageous for particular applications such as for deposition or formation on flexible substrates. Examples of organic opto-electronic devices include organic light emitting devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors.
For OLEDs, the organic materials are believed to have performance advantages over conventional materials. For example, the wavelength at which an organic emissive layer emits light may generally be readily tuned with appropriate dopants. OLEDs make use of thin organic films that emit light when voltage is applied across the device. OLEDs are becoming an increasingly interesting technology for use in applications such as flat panel displays, illumination, and backlighting.
The substrates as well as a fine metal mask are often held on a substrate support using mechanical force. Conventional mechanical contacts used to hold the substrate and the mask during processing may often result in substrate damage due to the high mechanical force applied. The mechanical force is further applied to hold the fine metal mask in place during processing. The conventional mechanical carriers generally hold the substrate at the edges, thus resulting in a highly concentrated physical contact at the edges of the substrate so as to ensure sufficient clamping force applied to securely pick up the substrate. This mechanical contact concentrated at the edges of the substrate inevitably creates contact contamination or physical damage, undesirably degrading the substrate.
Newer processing systems have incorporated alternative mechanisms for chucking the substrate to avoid the above described damage, such as holding the substrate in place using electrostatic force. Electrostatic force can effectively hold the substrate in position during processing while minimizing contact between metal components of the system and the substrate. However, the electrostatic force used for chucking the substrate cannot effectively chuck the mask in position as well.
Therefore, there is a need for a method and apparatus for positioning a mask independently of the substrates in a processing system.